Purpose

This is a study of ADI-PEG 20 (pegylated arginine deiminase), an arginine degrading enzyme versus placebo in patients with hepatocellular carcinoma who have failed prior systemic treatment (chemotherapy). Hepatocellular carcinomas have been found to require arginine, an amino acid. Thus the hypothesis is that by restricting arginine with ADI-PEG 20, the hepatocellular carcinoma cells will starve and die.